The present invention generally relates to controllers for operatively controlling devices in a control network, and more particularly to an application specific controller having features for changing the operating mode of the device in the field.
Controllers for controlling specific applications of devices in a system built around a control network is well known in the art. A heating/ventilation/air conditioning (HVAC) system is one such control network system. These application specific controllers (ASCs) in a HVAC system, are typically employed as single room controllers in a building, and control up to about five or six HVAC devices. For example, an ASC might control a damper that allows outside air into a room, a valve that permits hot water to run through a coil to heat the air or a fan that pulls air from the room over the heating coil.
The ASCs are typically programmed at the factory during assembly in accordance with the design specification of the control network system in which the ASCs are intended to be implemented. Once the ASCs have been installed in the system, it is often very difficult and complicated to reprogram the ASCs in the field, should the need arise. For example, an ASC for a HVAC system may have been preprogrammed at the factory to allow the temperature of the room to be maintained at a higher predetermined temperature during the night than in the day. If, however, it is decided after the ASC has been installed in the HVAC system that the cooling should be completely disabled at night. It would be a complicated task for a technician to reconfigure the ASC to perform the new task.